Design principles of combustion test dummies

The combustion test dummy system primarily consists of a test dummy, a data acquisition device, a flame generation and control device, a skin heat transfer model and burn assessment model, and a centralized system control and application software platform. The design principle simulates the thermal exposure of a clothed person to a burning flame, measuring changes in the dummy's surface temperature and estimating the potential for second- and third-degree burns and the percentage of total burn area. The greater the percentage of burn area, the poorer the garment's flame retardant performance.

Shanghai Qianshi Precision Electromechanical Technology Co., Ltd., established in 2012. specializes in the research, development, design, and production of textile testing instruments, providing textile testing equipment and services to academic research institutions and testing organizations. Shanghai Qianshi is one of the most competitive and R&D-capable textile testing instrument manufacturers in China. Our R&D team is comprised of experienced engineers. We are committed to wholeheartedly serving our customers and striving to promote technological innovation in textile testing equipment.

Dummy Body:

Based on the design requirements and through comparative analysis of the physical properties of high-temperature resistant materials, polyimide, currently available with high temperature resistance and excellent mechanical, dielectric, and corrosion resistance, was selected as the primary material for the combustion test dummy body. Based on the dummy model's appearance, the following process was used to manufacture the dummy body: polyimide synthesis → resin curing → mold creation of various anatomical segments and high-temperature molding → vacuum curing → surface treatment.

Dummy Surface Thermal Sensor:

The dummy skin surface thermal sensor senses the degree of heat exposure to human skin in a fire environment and predicts the potential severity of burns. Thermal sensors used internationally primarily include TPP copper sheet heat flux sensors, insulated copper sheet sensors, and embedded thermocouple sensors. Of these three types, the insulated copper sheet sensor is the most reliable.

Experiments have shown that the insulated copper sheet sensor, similar to the TPP copper sheet heat flux sensor, offers stable readings, rapid response, a wide range, and good repeatability. Furthermore, the sensor is smaller than the TPP sensor, occupying significantly less space and weighing less. In high-temperature environments, the average response speed of embedded thermocouple sensors is slower than that of insulated copper sheet sensors. Therefore, the research team developed an insulated copper sheet sensor with a diameter of 1 cm and a thickness of 0.16 cm. Using a brazing process, the copper sheet was connected to a K-type thermocouple with a wire diameter of 0.2 mm, achieving a measurement accuracy of 0.2°C.

Sensor Placement:

Taking into account factors such as the manikin's surface area, data collection, and burn assessment calculation, 120 insulated copper sheet sensors were evenly distributed across the manikin's surface. During sensor installation, a milling cutter drilled holes according to the diameter and depth of the copper sheet to ensure a close fit between the sensor surface and the surrounding area and the manikin itself, ensuring uniform sensor distribution.

Data Acquisition Device:

The data acquisition device primarily collects and processes the temperature signals from the 120 thermocouples on the manikin's surface. To ensure synchronous and high-speed acquisition of 120 temperature signals, 20 data acquisition and processing units were designed. Each unit consists of a main control CPU, AD acquisition circuit, real-time clock circuit, power supply circuit, and thermocouple temperature sensors.

Flame Generation and Control Device:

The flame generation and control device primarily produces the combustion flame required for garment flame retardant performance testing. It includes three components: fuel selection, gas pipeline design, and burner.

Fuel Selection:

Based on a comparison and analysis of the physical and chemical properties of commonly used clean, combustible gases, propane was selected as the fuel for the test system. Propane is widely available and forms water vapor and carbon dioxide upon combustion. It is an environmentally friendly fuel with a high calorific value, a low boiling point, and excellent safety, making it suitable for use in colder northern laboratories.